NumberResearchRecent prefix assignments
0 prefixes assigned in the last 30 days · from the daily NANPA CO code file, 09/20/2026
The Code holder is who opened each NPA-NXX prefix — not necessarily who holds the numbers. A prefix is 10,000 numbers, but under pooling its ten 1,000-number blocks are handed out individually, often to different carriers; the code holder may hold only one block, or none. The Thousands-blocks column shows how the ten blocks are really split — click which blocks → to see who holds each 1,000-number block and its last-4-digit range. Assignments are initial assignments; the current serving carrier may differ due to portability.
| Assigned | NPA-NXX | Thousands-blocks taken (last-4 opening) | Code holder | OCN | Rate center | State |
|---|---|---|---|---|---|---|
| 2015-09-30 | 586-272 | 0–9 XXXall 10 · 3 holders which blocks → | COMCAST IP PHONE, LLC | 318J | WARREN | MI |
| 2015-04-13 | 586-785 | 0–9 XXXall 10 · 5 holders which blocks → | COMCAST IP PHONE, LLC | 318J | ROMEO | MI |
| 2015-03-26 | 586-488 | 0–9 XXXall 10 · 4 holders which blocks → | COMCAST IP PHONE, LLC | 318J | UTICA | MI |
| 2015-03-14 | 586-204 | 0–9 XXXall 10 · 4 holders which blocks → | COMCAST IP PHONE, LLC | 318J | ROSEVILLE | MI |
| 2014-10-24 | 586-238 | 0–9 XXXall 10 · 5 holders which blocks → | COMCAST IP PHONE, LLC | 318J | ROSEVILLE | MI |
| 2014-07-01 | 586-213 | 0XXX1XXX2XXX3XXX5XXX8XXX9XXX · 4 holders which blocks → | COMCAST IP PHONE, LLC | 318J | MT CLEMENS | MI |
| 2013-04-10 | 586-200 | 0–9 XXXall 10 · 7 holders which blocks → | COMCAST IP PHONE, LLC | 318J | ROSEVILLE | MI |
| 2008-06-19 | 586-231 | 0–9 XXXall 10 · 5 holders which blocks → | COMCAST IP PHONE, LLC | 318J | MT CLEMENS | MI |
| 2007-07-10 | 586-275 | 0–9 XXXall 10 · 6 holders which blocks → | COMCAST IP PHONE, LLC | 318J | WARREN | MI |
| — | 586-883 | 0XXX1XXX2XXX3XXX4XXX5XXX8XXX · 2 holders which blocks → | COMCAST IP PHONE, LLC | 318J | WARREN | MI |
Source: NANPA CO Code Assignments (Utilized, All States, Public), file date 09/20/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.